Coil spring lock

ABSTRACT

An upholstery spring is disclosed, consisting of a length of wire helically coiled with the end convolutions closed to define two circles. The wire ends are wrapped about the adjacent turn at points where an obtuse elbow is located. The wire end crosses inwardly against the elbow and then wraps around the wire immediately adjacent the bend, to trap one leg of the elbow between the wrapped end and the portion crossing inwardly against the elbow, thereby preventing the wire end from slipping on the adjacent turn.

United States Patent 1 Kaiser Oct. 23, 1973 COIL SPRING LOCK [76]Inventor: Martin Kaiser, 66 Spencer Ave.,

Toronto 3, Ontario, Canada [22] Filed: June 17, 1971 [21] Appl. No.:153,969

[52] US. Cl. 267/91, 267/179 [51] Int. Cl Fl6t 3/04 [58] Field of Search267/142, 91, 179, 267/1; 5/260, 256

[56] References Cited UNITED STATES PATENTS 2,161,165 6/1939 Hirschman267/142 2,641,758 6/1953 Levine 267/142 2,249,999 7/1941 Asaro.....5/260 3,190,631 6/1965 Kaiser 267/179 FOREIGN PATENTS OR APPLICATIONS1,191,747 10/1959 France 267/147 Primary Examiner-James B. MarbertAt!orneySim et al.

[57] ABSTRACT An upholstery spring is disclosed, consisting of a lengthof wire helically coiled with the end convolutions closed to define twocircles. The wire ends are wrapped about the adjacent turn at pointswhere an obtuse elbow is located. The wire end crosses inwardly againstthe elbow and then wraps around the wire immediately adjacent the bend,totrap one leg of the elbow between the wrapped end and the portioncrossing inwardly against the elbow, thereby preventing the wire endfrom slipping on the adjacent turn.

6 Claims, 3 Drawing Figures Patented Oct. 23, 1973 mmgnm INVENTOR.MARTIN KAISER gaw M gwuw Aqent con. SPRING LOCK This invention relatesgenerally to spring-filled furniture such as mattresses, box springs,chesterfields, chairs and the like, and has to do particularly with animproved form of the conventional upright helical springs which areutilized in the construction of these items.

The conventional upright helical spring utilized in the manufacture ofmattresses, chesterfields, etc. is made from a single piece of wirewhich is configured to define a helix of about four or fiveconvolutions, the end convolutions being of larger diameter than theintermediate convolutions. Usually, the end convolutions are closed toform closed end coils, and the closure takes place by wrapping the wireend tightly about the wire where it begins to define the adjacentconvolution. Generally speaking, the upper and lower coils aresubstantially circular and lie in parallel spaced-apart planes atright-angles to the spring axis.

One of the most difficult aspects of manufacturing these upright helicalsprings is related to the tendency of the end coils to increase indiameter upon compression of the spring and to decrease indiameter uponsubsequent expansion of the spring. This tends to urge the wrapped endsof the spring wire to move along the adjacent convolution, a movementwhich is made easier by the fact that when the internalconvolutions ofthe spring are flattened the wire tends to twist within the wrappedends.

Some attempts have been made in the prior art to overcome thisdifficulty by attempting to limit. the movement of the wrapped end uponthe adjacent convolution, usually by joggling or bending the main wireat the point where the end is wrapped upon it.

Exemplary of the prior art in this respect is my own U.S. Pat. No.3,190,631, issued June 22, 1,965, and entitled Coil Spring Lock. Whilethe spring configuration disclosed in my earlier U.S. Pat. No. 3,190,631represents an improvement over the previous techniques, I havenonetheless found some difficulty in achieving an absolutely tightandimmovable grip of the wire end on the adjacent convolution, thereason for this being that the construction in my U.S. Pat. No.3,190,631 has the wrapped wire end coiled about a portion of wire havinga bend at either end. The difficulty arises in attempting to positionthese two bends at exactly the right spacing so that the wrapped wireend cannot budge.

I have now discovered a construction which achieves an immovable grip ofthe coiled wire end on the adja cent convolution, and which at the sametime obviates the necessity for one of the bends at the location on theadjacent convolution where the wire end is to be wrapped.

Essentially, the improvement I have now discovered is to provide onlyone bend in the adjacent ocnvolution, to bend the portion adjacent thefree end of the wire obliquely inwardly within the plane of the end coilto abut the bend cross-wise, and then to coil the end of the wire aboutthe end coil immediately adjacent the bend, in such a way that the wireend forms a helix of the opposite sense from the helix of the spring. Inother words, if the spring helix is clockwise, the wire end wrappinghelix is counter-clockwise.

More specifically, this invention provides an upholstery springcomprising a single length of wire having two ends and configured todefine a substantially helical spring, the. helical spring including aplurality of convolutions, of which an end convolution is closed todefine an end coil of substantially circular shape lying substantiallyin a single plane, the end coil being closed by having the respectiveend of the wire wrapped about the wire where the end coil merges withthe adjacent convolution, the portion of the wire which links the endcoil with the adjacent convolution being bent obliquely away from theplane of the end coil to define an obtuse angle at the point of merging,the portion of the wire immediately adjacent said respective end of thewire being bent inwardly in said plane so as to abut said ohtuse angle,the end of the wire being wrapped tightly in a helix of the oppositesense from the helix of the spring at least two full turns around thewire in the end coil immediately adjacent said obtuse angle.

One embodiment of this invention is shown in the accompanying drawings,in which like numerals denote like parts throughout the several views,and in which:

FIG. 1 is a perspective view of a completed upright helical springincorporating the improvement of this invention;

FIG. 2 is a plan view of the lower end coil and a portion of theadjacent convolution of the spring of FIG. 1; and

FIG. 3 is an elevational view of the lower end coil shown in FIG. 2.

Attention is first directed to FIG. 1, which shows an upholstery spring10 which is made from a single length of wire 11 configured to definesubstantially a helix of which the middle convslutions 12 are of smallerdiameter than the end convolutions l4 and 16. The wire 11 has two ends17 and 18. The end 17 is brought against and wrapped around the wire 1 1to define an upper end coil 20, while the end 18 is brouhgt against andwrapped around the wire 11 to define a lower end coil 22. The end coils20 and 22 are substantially circular and lie substantially inspaced-apart parallel planes.

As can be seen in the Figures, the portion of the wire 11 which linksthe lower end coil 22 with the adjacent convolution 23 is bent obliquelyupwardly from the plane in which the lower end coil 22 is located, anddefines an obtuse angle in a vertical plane at the point where the endcoil 22 merges with the adjacent convolution 23. The obtuse angle isindicated by the number 25 in FIG. 3 and the location of the bend islabelled with the number 27. The bend at 27 is not a precise sharp bend,as this would weaken the spring material. The bend at 27 is in fact acurve with a very small radius, but is sharp enough to be spoken of as abend. The portion of the wire immediately adjacent the end 18, generallyindicated by the numeral 30 is bent inwardly in the plane of the lowerend coil 22 so as to abut the obtuse angle elbow at the point 27 in across-wise fashion. This is clear from FIGS. 2 and 3, which show theportion 30 bending toward the centre of the circular bottom coil 22 andcutting directly across and against the elbow at the point 27. Then, theend of the wire passes inwardly, upwardly and tightly around the part ofthe wire in the lower end coil 22 which is immediately adjacent theelbow at 27. It will be noted that the end 18 is wrapped at least twofull turns, and that these turns are tightly wrapped against each other.Furthermore, the direction of wrapping the end 18 in a helix has theopposite sense from the helix of the spring 10. This latter featureisessential to this invention. It will be noted in the embodiment shownthat the helical spring of FIG. 1 is a clockwise helix, while thewrapping of the end 18 is a counter-clockwise helix.

Naturally, if the helical spring 10 were a counterclockwise helix, thewrapping of the end 18 would be a clockwise helix.

The identical attachment configuration takes place at the upper end coil20, but because this is identical it has not been shown in separateFigures. It will be noted, however, that the helical wrap of the end 17is also counter-clockwise, the same as that of the end 18.

Because the ends 17 and 18 are wrapped tightly up against the elbows,such as the elbow 27 in the lower end coil 22, and because the wireimmediately adjacent the end is bent inwardly to cut across the elbow,the join between the ends 17 and 18 and the wire 11 is impossible tomove with respect to the wire 11. Looking at FIGS. 2 and 3, the portion30 of the wire prevents the point of attachment from sliding leftwardly(as viewed in FIG. 3) along the wire 11, while the wrapped coils of theend 18, hard up against the elbow at 27, prevent the point of attachmentfrom sliding to the right.

It is thus seen that the construction herein disclosed requires only asingle bend at the point of attachment, but yields a very secure joint.

In order to compensate for the inward bend at 30 in FIGS. 2 and 3, theportion 32 of the lower end coil 22 (immediately adjacent the elbow at27) should be bent slightly inwardly and straightened to some extent. Itwill be noted in FIG. 2 that this inward bending does not cause the coil22 to depart seriously from circularity.

What I claim as my invention is:

1. An upholstery spring comprising a single length of wire having twoends and configured to define a substantially helical spring, thehelical spring including a plurality of convolutions, of which an endconvolution is closed to define an end coil of substantially circularshape lying substantially in a single plane, the end coil being closedby having the respective end of the wire wrapped about the wire wherethe end coil merges with the adjacent convolution, the portion of thewire which links the end coil with the adjacent convolution being bentobliquely away from the plane of the end coil to define an obtuse angleat the point of merging, one arm of the obtuse angle lying in saidplane, the portion of the wire immediately adjacent said respective endof the wire being bent inwardly in said plane so as to abut said obtuseangle, the end of the wire being wrapped tightly in a helix of theopposite sense from the helix of the spring at least two full turnsaround the wire in the end coil immediately adjacent said obtuse angle.

2. An upholstery spring as claimed in claim 1, in which both endconvolutions are closed to define end coils, the end coils lying inspaced parallel planes.

3. An upholstery spring as claimed in claim 2, in which the convolutionsintermediate the end coils are of smaller diameter than the end coils.

4. An upholstery spring as claimed in claim 1, in which the helix of thespring is a clockwise helix while the helix of the wrapped wire end is acounterclockwise helix.

5. An upholstery spring as claimed in claim 1, in which the portion ofthe end coil immediately adjacent the obtuse angle is bent slightlyinwardly away from circularity and is substantially straight.

6. An upholstery spring as claimed in claim 3, in which the helix of thespring is a clockwise helix, and in which the portion of the end coilimmediately adjacent the obtuse angle is bent slightly inwardly awayfrom circularity and is substantially straight.

1. An upholstery spring comprising a single length of wire having two ends and configured to define a substantially helical spring, the helical spring including a plurality of convolutions, of which an end convolution is closed to define an end coil of substantially circular shape lying substantially in a single plane, the end coil being closed by having the respective end of the wire wrapped about the wire where the end coil merges with the adjacent convolution, the portion of the wire which links the end coil with the adjacent convolution being bent obliquely away from the plane of the end coil to define an obtuse angle at the point of merging, one arm of the obtuse angle lying in said plane, the portion of the wire immediately adjacent said respective end of the wire being bent inwardly in said plane so as to abut said obtuse angle, the end of the wire being wrapped tightly in a helix of the opposite sense from the helix of the spring at least two full turns around the wire in the end coil immediately adjacent said obtuse angle.
 2. An upholstery spring as claimed in claim 1, in which both end convolutions are closed to define end coils, the end coils lying in spaced parallel planes.
 3. An upholstery spring as claimed in claim 2, in which the convolutions intermediate the end coils are of smaller diameter than the end coils.
 4. An upholstery spring as claimed in claim 1, in which the helix of the spring is a clockwise helix while the helix of the wrapped wire end is a counter-clockwise helix.
 5. An upholstery spring as claimed in claim 1, in which the portion of the end coil immediately adjacent the obtuse angle is bent slightly inwardly away from circularity and is substantially straight.
 6. An upholstery spring as claimed in claim 3, in which the helix of the spring is a clockwise helix, and in which the portion of the end coil immediately adjacent the obtuse angle is bent slightly inwardly away from circularity and is substantially straight. 